US and Australia both predict likely 2014 El Nino bringing rain to California in summer or fall. Historically El Nino years have brought most rain to California-SF Gate, Reuters

"But even as hope dims for a March miracle storm, climatologists say
weatherconditions could change this year if an El Niño takes shape. TheU.S. Climate Prediction Center
issued an El Niño watch this month, citing a 52 percent chance of
Pacific Ocean waters warming and creating - possibly - a
wetter-than-average winter.

Historically, El Niño conditions have been associated with the
state's biggest rain years, including the winters of 1997-98 and
1982-83, which brought fatal mudslides to the Santa Cruz Mountains and
devastating surf to the Southern California coast. In 1997-98, San
Francisco was pounded by a record 47.2 inches of rain.

"If it's only in the weak to moderate category, it doesn't really make me convinced that things will turn around," said state Department of Water Resources climatologist Mike Anderson, who plans to monitor the telltale phenomenon as fall approaches. "We've still got a long, hot summer to go."

To date, San Francisco has received just 8.6 inches of rain since
July. That compares with the 20.3 inches that falls on average by this
point in the rain year.

The story of below-average precipitation is the same across the state....

In the Central Valley, the state and federal water projects that
provide Sierra snowmelt to farmers say they're likely to have no water
to give out this year.

The short-term forecast doesn't look good. The National Weather Service is calling for a small chance of rain in the Bay Area around the middle of next week, but no more than half an inch.

"We would need five times the amount of normal rainfall every day between now and June to get us back to normal levels," said Steve Anderson, a forecaster for the weather service.

Climatologists looking at the long-term picture, meanwhile, say ocean
temperature readings and wind models suggest that an El Niño may form
over the eastern tropics of the Pacific Ocean in the summer or fall.

"It's a long way from being a slam dunk," said Mike Halpert, acting director of the Climate Prediction Center.

The water and atmospheric conditions, Halpert said, have the
potential to feed off each other and prompt major shifts in world
weather patterns.

For example, weak to moderate El Niño conditions have brought more
rain to Southern California, while doing little for the northern part of
the state. But a strong El Niño historically has increased rainfall
across the entire state.

With the state in its third straight drier-than-average year, rain in
the northern half is particularly important. That's where most of the
water supply is stored in the forms of snow, rivers and creeks."via Zero Hedge

The Australian Bureau of Meteorology
(BOM) said an El Nino could occur during the southern hemisphere
winter, May-July, with Australian cattle and grain farmers already
struggling with drought which has cut production.

The last El Nino in 2009/10 was categorised weak to moderate. The
most severe El Nino was in 1998 when freak weather killed more than
2,000 people and caused billions of dollars in damage to crops,
infrastructure and mines in Australia and other parts of Asia.

"The latest climate model survey...shows that the tropical Pacific
is very likely to warm in the coming months, with most models showing
sea surface temperatures reaching El Nino thresholds during the southern
hemisphere winter," the BOM said in an emailed statement.